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 * Copyright (c) 1997, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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package javax.swing;

import java.awt.Component;
import java.util.ArrayList;
import java.util.Hashtable;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Rectangle;
import sun.awt.SunToolkit;

import javax.accessibility.*;

/**
 * <code>JLayeredPane</code> adds depth to a JFC/Swing container, allowing components to overlap
 * each other when needed. An <code>Integer</code> object specifies each component's depth in the
 * container, where higher-numbered components sit &quot;on top&quot; of other components. For
 * task-oriented documentation and examples of using layered panes see <a
 * href="https://docs.oracle.com/javase/tutorial/uiswing/components/layeredpane.html">How to Use a
 * Layered Pane</a>, a section in <em>The Java Tutorial</em>.
 *
 * <TABLE STYLE="FLOAT:RIGHT" BORDER="0" SUMMARY="layout"> <TR> <TD ALIGN="CENTER"> <P
 * STYLE="TEXT-ALIGN:CENTER"><IMG SRC="doc-files/JLayeredPane-1.gif" alt="The following text
 * describes this image." WIDTH="269" HEIGHT="264" STYLE="FLOAT:BOTTOM; BORDER=0"> </TD> </TR>
 * </TABLE> For convenience, <code>JLayeredPane</code> divides the depth-range into several
 * different layers. Putting a component into one of those layers makes it easy to ensure that
 * components overlap properly, without having to worry about specifying numbers for specific
 * depths: <DL> <DT><FONT SIZE="2">DEFAULT_LAYER</FONT></DT> <DD>The standard layer, where most
 * components go. This the bottommost layer. <DT><FONT SIZE="2">PALETTE_LAYER</FONT></DT> <DD>The
 * palette layer sits over the default layer. Useful for floating toolbars and palettes, so they can
 * be positioned above other components. <DT><FONT SIZE="2">MODAL_LAYER</FONT></DT> <DD>The layer
 * used for modal dialogs. They will appear on top of any toolbars, palettes, or standard components
 * in the container. <DT><FONT SIZE="2">POPUP_LAYER</FONT></DT> <DD>The popup layer displays above
 * dialogs. That way, the popup windows associated with combo boxes, tooltips, and other help text
 * will appear above the component, palette, or dialog that generated them. <DT><FONT
 * SIZE="2">DRAG_LAYER</FONT></DT> <DD>When dragging a component, reassigning it to the drag layer
 * ensures that it is positioned over every other component in the container. When finished
 * dragging, it can be reassigned to its normal layer. </DL> The <code>JLayeredPane</code> methods
 * <code>moveToFront(Component)</code>, <code>moveToBack(Component)</code> and
 * <code>setPosition</code> can be used to reposition a component within its layer. The
 * <code>setLayer</code> method can also be used to change the component's current layer.
 *
 * <h2>Details</h2> <code>JLayeredPane</code> manages its list of children like
 * <code>Container</code>, but allows for the definition of a several layers within itself. Children
 * in the same layer are managed exactly like the normal <code>Container</code> object, with the
 * added feature that when children components overlap, children in higher layers display above the
 * children in lower layers. <p> Each layer is a distinct integer number. The layer attribute can be
 * set on a <code>Component</code> by passing an <code>Integer</code> object during the add
 * call.<br> For example: <PRE> layeredPane.add(child, JLayeredPane.DEFAULT_LAYER); or
 * layeredPane.add(child, new Integer(10)); </PRE> The layer attribute can also be set on a
 * Component by calling<PRE> layeredPaneParent.setLayer(child, 10)</PRE> on the
 * <code>JLayeredPane</code> that is the parent of component. The layer should be set <i>before</i>
 * adding the child to the parent. <p> Higher number layers display above lower number layers. So,
 * using numbers for the layers and letters for individual components, a representative list order
 * would look like this:<PRE> 5a, 5b, 5c, 2a, 2b, 2c, 1a </PRE> where the leftmost components are
 * closest to the top of the display. <p> A component can be moved to the top or bottom position
 * within its layer by calling <code>moveToFront</code> or <code>moveToBack</code>. <p> The position
 * of a component within a layer can also be specified directly. Valid positions range from 0 up to
 * one less than the number of components in that layer. A value of -1 indicates the bottommost
 * position. A value of 0 indicates the topmost position. Unlike layer numbers, higher position
 * values are <i>lower</i> in the display. <blockquote> <b>Note:</b> This sequence (defined by
 * java.awt.Container) is the reverse of the layer numbering sequence. Usually though, you will use
 * <code>moveToFront</code>, <code>moveToBack</code>, and <code>setLayer</code>. </blockquote> Here
 * are some examples using the method add(Component, layer, position): Calling add(5x, 5, -1)
 * results in:<PRE> 5a, 5b, 5c, 5x, 2a, 2b, 2c, 1a </PRE>
 *
 * Calling add(5z, 5, 2) results in:<PRE> 5a, 5b, 5z, 5c, 5x, 2a, 2b, 2c, 1a </PRE>
 *
 * Calling add(3a, 3, 7) results in:<PRE> 5a, 5b, 5z, 5c, 5x, 3a, 2a, 2b, 2c, 1a </PRE>
 *
 * Using normal paint/event mechanics results in 1a appearing at the bottom and 5a being above all
 * other components. <p> <b>Note:</b> that these layers are simply a logical construct and
 * LayoutManagers will affect all child components of this container without regard for layer
 * settings. <p> <strong>Warning:</strong> Swing is not thread safe. For more information see <a
 * href="package-summary.html#threading">Swing's Threading Policy</a>. <p> <strong>Warning:</strong>
 * Serialized objects of this class will not be compatible with future Swing releases. The current
 * serialization support is appropriate for short term storage or RMI between applications running
 * the same version of Swing.  As of 1.4, support for long term storage of all JavaBeans&trade; has
 * been added to the <code>java.beans</code> package. Please see {@link java.beans.XMLEncoder}.
 *
 * @author David Kloba
 */
@SuppressWarnings("serial")
public class JLayeredPane extends JComponent implements Accessible {
  /// Watch the values in getObjectForLayer()
  /**
   * Convenience object defining the Default layer. Equivalent to new Integer(0).
   */
  public final static Integer DEFAULT_LAYER = new Integer(0);
  /**
   * Convenience object defining the Palette layer. Equivalent to new Integer(100).
   */
  public final static Integer PALETTE_LAYER = new Integer(100);
  /**
   * Convenience object defining the Modal layer. Equivalent to new Integer(200).
   */
  public final static Integer MODAL_LAYER = new Integer(200);
  /**
   * Convenience object defining the Popup layer. Equivalent to new Integer(300).
   */
  public final static Integer POPUP_LAYER = new Integer(300);
  /**
   * Convenience object defining the Drag layer. Equivalent to new Integer(400).
   */
  public final static Integer DRAG_LAYER = new Integer(400);
  /**
   * Convenience object defining the Frame Content layer.
   * This layer is normally only use to position the contentPane and menuBar
   * components of JFrame.
   * Equivalent to new Integer(-30000).
   *
   * @see JFrame
   */
  public final static Integer FRAME_CONTENT_LAYER = new Integer(-30000);

  /**
   * Bound property
   */
  public final static String LAYER_PROPERTY = "layeredContainerLayer";
  // Hashtable to store layer values for non-JComponent components
  private Hashtable<Component, Integer> componentToLayer;
  private boolean optimizedDrawingPossible = true;

//////////////////////////////////////////////////////////////////////////////
//// Container Override methods
//////////////////////////////////////////////////////////////////////////////

  /**
   * Create a new JLayeredPane
   */
  public JLayeredPane() {
    setLayout(null);
  }

  private void validateOptimizedDrawing() {
    boolean layeredComponentFound = false;
    synchronized (getTreeLock()) {
      Integer layer;

      for (Component c : getComponents()) {
        layer = null;

        if (SunToolkit.isInstanceOf(c, "javax.swing.JInternalFrame") ||
            (c instanceof JComponent &&
                (layer = (Integer) ((JComponent) c).
                    getClientProperty(LAYER_PROPERTY)) != null)) {
          if (layer != null && layer.equals(FRAME_CONTENT_LAYER)) {
            continue;
          }
          layeredComponentFound = true;
          break;
        }
      }
    }

    if (layeredComponentFound) {
      optimizedDrawingPossible = false;
    } else {
      optimizedDrawingPossible = true;
    }
  }

  protected void addImpl(Component comp, Object constraints, int index) {
    int layer;
    int pos;

    if (constraints instanceof Integer) {
      layer = ((Integer) constraints).intValue();
      setLayer(comp, layer);
    } else {
      layer = getLayer(comp);
    }

    pos = insertIndexForLayer(layer, index);
    super.addImpl(comp, constraints, pos);
    comp.validate();
    comp.repaint();
    validateOptimizedDrawing();
  }

  /**
   * Remove the indexed component from this pane.
   * This is the absolute index, ignoring layers.
   *
   * @param index an int specifying the component to remove
   * @see #getIndexOf
   */
  public void remove(int index) {
    Component c = getComponent(index);
    super.remove(index);
    if (c != null && !(c instanceof JComponent)) {
      getComponentToLayer().remove(c);
    }
    validateOptimizedDrawing();
  }

  /**
   * Removes all the components from this container.
   *
   * @since 1.5
   */
  public void removeAll() {
    Component[] children = getComponents();
    Hashtable<Component, Integer> cToL = getComponentToLayer();
    for (int counter = children.length - 1; counter >= 0; counter--) {
      Component c = children[counter];
      if (c != null && !(c instanceof JComponent)) {
        cToL.remove(c);
      }
    }
    super.removeAll();
  }

  /**
   * Returns false if components in the pane can overlap, which makes
   * optimized drawing impossible. Otherwise, returns true.
   *
   * @return false if components can overlap, else true
   * @see JComponent#isOptimizedDrawingEnabled
   */
  public boolean isOptimizedDrawingEnabled() {
    return optimizedDrawingPossible;
  }

//////////////////////////////////////////////////////////////////////////////
//// New methods for managing layers
//////////////////////////////////////////////////////////////////////////////

  /**
   * Sets the layer property on a JComponent. This method does not cause
   * any side effects like setLayer() (painting, add/remove, etc).
   * Normally you should use the instance method setLayer(), in order to
   * get the desired side-effects (like repainting).
   *
   * @param c the JComponent to move
   * @param layer an int specifying the layer to move it to
   * @see #setLayer
   */
  public static void putLayer(JComponent c, int layer) {
    /// MAKE SURE THIS AND setLayer(Component c, int layer, int position)  are SYNCED
    Integer layerObj;

    layerObj = new Integer(layer);
    c.putClientProperty(LAYER_PROPERTY, layerObj);
  }

  /**
   * Gets the layer property for a JComponent, it
   * does not cause any side effects like setLayer(). (painting, add/remove, etc)
   * Normally you should use the instance method getLayer().
   *
   * @param c the JComponent to check
   * @return an int specifying the component's layer
   */
  public static int getLayer(JComponent c) {
    Integer i;
    if ((i = (Integer) c.getClientProperty(LAYER_PROPERTY)) != null) {
      return i.intValue();
    }
    return DEFAULT_LAYER.intValue();
  }

  /**
   * Convenience method that returns the first JLayeredPane which
   * contains the specified component. Note that all JFrames have a
   * JLayeredPane at their root, so any component in a JFrame will
   * have a JLayeredPane parent.
   *
   * @param c the Component to check
   * @return the JLayeredPane that contains the component, or null if no JLayeredPane is found in
   * the component hierarchy
   * @see JFrame
   * @see JRootPane
   */
  public static JLayeredPane getLayeredPaneAbove(Component c) {
    if (c == null) {
      return null;
    }

    Component parent = c.getParent();
    while (parent != null && !(parent instanceof JLayeredPane)) {
      parent = parent.getParent();
    }
    return (JLayeredPane) parent;
  }

  /**
   * Sets the layer attribute on the specified component,
   * making it the bottommost component in that layer.
   * Should be called before adding to parent.
   *
   * @param c the Component to set the layer for
   * @param layer an int specifying the layer to set, where lower numbers are closer to the bottom
   */
  public void setLayer(Component c, int layer) {
    setLayer(c, layer, -1);
  }

  /**
   * Sets the layer attribute for the specified component and
   * also sets its position within that layer.
   *
   * @param c the Component to set the layer for
   * @param layer an int specifying the layer to set, where lower numbers are closer to the bottom
   * @param position an int specifying the position within the layer, where 0 is the topmost
   * position and -1 is the bottommost position
   */
  public void setLayer(Component c, int layer, int position) {
    Integer layerObj;
    layerObj = getObjectForLayer(layer);

    if (layer == getLayer(c) && position == getPosition(c)) {
      repaint(c.getBounds());
      return;
    }

    /// MAKE SURE THIS AND putLayer(JComponent c, int layer) are SYNCED
    if (c instanceof JComponent) {
      ((JComponent) c).putClientProperty(LAYER_PROPERTY, layerObj);
    } else {
      getComponentToLayer().put(c, layerObj);
    }

    if (c.getParent() == null || c.getParent() != this) {
      repaint(c.getBounds());
      return;
    }

    int index = insertIndexForLayer(c, layer, position);

    setComponentZOrder(c, index);
    repaint(c.getBounds());
  }

  /**
   * Returns the layer attribute for the specified Component.
   *
   * @param c the Component to check
   * @return an int specifying the component's current layer
   */
  public int getLayer(Component c) {
    Integer i;
    if (c instanceof JComponent) {
      i = (Integer) ((JComponent) c).getClientProperty(LAYER_PROPERTY);
    } else {
      i = getComponentToLayer().get(c);
    }

    if (i == null) {
      return DEFAULT_LAYER.intValue();
    }
    return i.intValue();
  }

  /**
   * Returns the index of the specified Component.
   * This is the absolute index, ignoring layers.
   * Index numbers, like position numbers, have the topmost component
   * at index zero. Larger numbers are closer to the bottom.
   *
   * @param c the Component to check
   * @return an int specifying the component's index
   */
  public int getIndexOf(Component c) {
    int i, count;

    count = getComponentCount();
    for (i = 0; i < count; i++) {
      if (c == getComponent(i)) {
        return i;
      }
    }
    return -1;
  }

  /**
   * Moves the component to the top of the components in its current layer
   * (position 0).
   *
   * @param c the Component to move
   * @see #setPosition(Component, int)
   */
  public void moveToFront(Component c) {
    setPosition(c, 0);
  }

  /**
   * Moves the component to the bottom of the components in its current layer
   * (position -1).
   *
   * @param c the Component to move
   * @see #setPosition(Component, int)
   */
  public void moveToBack(Component c) {
    setPosition(c, -1);
  }

  /**
   * Moves the component to <code>position</code> within its current layer,
   * where 0 is the topmost position within the layer and -1 is the bottommost
   * position.
   * <p>
   * <b>Note:</b> Position numbering is defined by java.awt.Container, and
   * is the opposite of layer numbering. Lower position numbers are closer
   * to the top (0 is topmost), and higher position numbers are closer to
   * the bottom.
   *
   * @param c the Component to move
   * @param position an int in the range -1..N-1, where N is the number of components in the
   * component's current layer
   */
  public void setPosition(Component c, int position) {
    setLayer(c, getLayer(c), position);
  }

  /**
   * Get the relative position of the component within its layer.
   *
   * @param c the Component to check
   * @return an int giving the component's position, where 0 is the topmost position and the highest
   * index value = the count count of components at that layer, minus 1
   * @see #getComponentCountInLayer
   */
  public int getPosition(Component c) {
    int i, startLayer, curLayer, startLocation, pos = 0;

    getComponentCount();
    startLocation = getIndexOf(c);

    if (startLocation == -1) {
      return -1;
    }

    startLayer = getLayer(c);
    for (i = startLocation - 1; i >= 0; i--) {
      curLayer = getLayer(getComponent(i));
      if (curLayer == startLayer) {
        pos++;
      } else {
        return pos;
      }
    }
    return pos;
  }

  /**
   * Returns the highest layer value from all current children.
   * Returns 0 if there are no children.
   *
   * @return an int indicating the layer of the topmost component in the pane, or zero if there are
   * no children
   */
  public int highestLayer() {
    if (getComponentCount() > 0) {
      return getLayer(getComponent(0));
    }
    return 0;
  }

  /**
   * Returns the lowest layer value from all current children.
   * Returns 0 if there are no children.
   *
   * @return an int indicating the layer of the bottommost component in the pane, or zero if there
   * are no children
   */
  public int lowestLayer() {
    int count = getComponentCount();
    if (count > 0) {
      return getLayer(getComponent(count - 1));
    }
    return 0;
  }

  /**
   * Returns the number of children currently in the specified layer.
   *
   * @param layer an int specifying the layer to check
   * @return an int specifying the number of components in that layer
   */
  public int getComponentCountInLayer(int layer) {
    int i, count, curLayer;
    int layerCount = 0;

    count = getComponentCount();
    for (i = 0; i < count; i++) {
      curLayer = getLayer(getComponent(i));
      if (curLayer == layer) {
        layerCount++;
        /// Short circut the counting when we have them all
      } else if (layerCount > 0 || curLayer < layer) {
        break;
      }
    }

    return layerCount;
  }

  /**
   * Returns an array of the components in the specified layer.
   *
   * @param layer an int specifying the layer to check
   * @return an array of Components contained in that layer
   */
  public Component[] getComponentsInLayer(int layer) {
    int i, count, curLayer;
    int layerCount = 0;
    Component[] results;

    results = new Component[getComponentCountInLayer(layer)];
    count = getComponentCount();
    for (i = 0; i < count; i++) {
      curLayer = getLayer(getComponent(i));
      if (curLayer == layer) {
        results[layerCount++] = getComponent(i);
        /// Short circut the counting when we have them all
      } else if (layerCount > 0 || curLayer < layer) {
        break;
      }
    }

    return results;
  }

  /**
   * Paints this JLayeredPane within the specified graphics context.
   *
   * @param g the Graphics context within which to paint
   */
  public void paint(Graphics g) {
    if (isOpaque()) {
      Rectangle r = g.getClipBounds();
      Color c = getBackground();
      if (c == null) {
        c = Color.lightGray;
      }
      g.setColor(c);
      if (r != null) {
        g.fillRect(r.x, r.y, r.width, r.height);
      } else {
        g.fillRect(0, 0, getWidth(), getHeight());
      }
    }
    super.paint(g);
  }

//////////////////////////////////////////////////////////////////////////////
//// Implementation Details
//////////////////////////////////////////////////////////////////////////////

  /**
   * Returns the hashtable that maps components to layers.
   *
   * @return the Hashtable used to map components to their layers
   */
  protected Hashtable<Component, Integer> getComponentToLayer() {
    if (componentToLayer == null) {
      componentToLayer = new Hashtable<Component, Integer>(4);
    }
    return componentToLayer;
  }

  /**
   * Returns the Integer object associated with a specified layer.
   *
   * @param layer an int specifying the layer
   * @return an Integer object for that layer
   */
  protected Integer getObjectForLayer(int layer) {
    Integer layerObj;
    switch (layer) {
      case 0:
        layerObj = DEFAULT_LAYER;
        break;
      case 100:
        layerObj = PALETTE_LAYER;
        break;
      case 200:
        layerObj = MODAL_LAYER;
        break;
      case 300:
        layerObj = POPUP_LAYER;
        break;
      case 400:
        layerObj = DRAG_LAYER;
        break;
      default:
        layerObj = new Integer(layer);
    }
    return layerObj;
  }

  /**
   * Primitive method that determines the proper location to
   * insert a new child based on layer and position requests.
   *
   * @param layer an int specifying the layer
   * @param position an int specifying the position within the layer
   * @return an int giving the (absolute) insertion-index
   * @see #getIndexOf
   */
  protected int insertIndexForLayer(int layer, int position) {
    return insertIndexForLayer(null, layer, position);
  }

  /**
   * This method is an extended version of insertIndexForLayer()
   * to support setLayer which uses Container.setZOrder which does
   * not remove the component from the containment hierarchy though
   * we need to ignore it when calculating the insertion index.
   *
   * @param comp component to ignore when determining index
   * @param layer an int specifying the layer
   * @param position an int specifying the position within the layer
   * @return an int giving the (absolute) insertion-index
   * @see #getIndexOf
   */
  private int insertIndexForLayer(Component comp, int layer, int position) {
    int i, count, curLayer;
    int layerStart = -1;
    int layerEnd = -1;
    int componentCount = getComponentCount();

    ArrayList<Component> compList =
        new ArrayList<Component>(componentCount);
    for (int index = 0; index < componentCount; index++) {
      if (getComponent(index) != comp) {
        compList.add(getComponent(index));
      }
    }

    count = compList.size();
    for (i = 0; i < count; i++) {
      curLayer = getLayer(compList.get(i));
      if (layerStart == -1 && curLayer == layer) {
        layerStart = i;
      }
      if (curLayer < layer) {
        if (i == 0) {
          // layer is greater than any current layer
          // [ ASSERT(layer > highestLayer()) ]
          layerStart = 0;
          layerEnd = 0;
        } else {
          layerEnd = i;
        }
        break;
      }
    }

    // layer requested is lower than any current layer
    // [ ASSERT(layer < lowestLayer()) ]
    // put it on the bottom of the stack
    if (layerStart == -1 && layerEnd == -1) {
      return count;
    }

    // In the case of a single layer entry handle the degenerative cases
    if (layerStart != -1 && layerEnd == -1) {
      layerEnd = count;
    }

    if (layerEnd != -1 && layerStart == -1) {
      layerStart = layerEnd;
    }

    // If we are adding to the bottom, return the last element
    if (position == -1) {
      return layerEnd;
    }

    // Otherwise make sure the requested position falls in the
    // proper range
    if (position > -1 && layerStart + position <= layerEnd) {
      return layerStart + position;
    }

    // Otherwise return the end of the layer
    return layerEnd;
  }

  /**
   * Returns a string representation of this JLayeredPane. This method
   * is intended to be used only for debugging purposes, and the
   * content and format of the returned string may vary between
   * implementations. The returned string may be empty but may not
   * be <code>null</code>.
   *
   * @return a string representation of this JLayeredPane.
   */
  protected String paramString() {
    String optimizedDrawingPossibleString = (optimizedDrawingPossible ?
        "true" : "false");

    return super.paramString() +
        ",optimizedDrawingPossible=" + optimizedDrawingPossibleString;
  }

/////////////////
// Accessibility support
////////////////

  /**
   * Gets the AccessibleContext associated with this JLayeredPane.
   * For layered panes, the AccessibleContext takes the form of an
   * AccessibleJLayeredPane.
   * A new AccessibleJLayeredPane instance is created if necessary.
   *
   * @return an AccessibleJLayeredPane that serves as the AccessibleContext of this JLayeredPane
   */
  public AccessibleContext getAccessibleContext() {
    if (accessibleContext == null) {
      accessibleContext = new AccessibleJLayeredPane();
    }
    return accessibleContext;
  }

  /**
   * This class implements accessibility support for the
   * <code>JLayeredPane</code> class.  It provides an implementation of the
   * Java Accessibility API appropriate to layered pane user-interface
   * elements.
   * <p>
   * <strong>Warning:</strong>
   * Serialized objects of this class will not be compatible with
   * future Swing releases. The current serialization support is
   * appropriate for short term storage or RMI between applications running
   * the same version of Swing.  As of 1.4, support for long term storage
   * of all JavaBeans&trade;
   * has been added to the <code>java.beans</code> package.
   * Please see {@link java.beans.XMLEncoder}.
   */
  @SuppressWarnings("serial")
  protected class AccessibleJLayeredPane extends AccessibleJComponent {

    /**
     * Get the role of this object.
     *
     * @return an instance of AccessibleRole describing the role of the object
     * @see AccessibleRole
     */
    public AccessibleRole getAccessibleRole() {
      return AccessibleRole.LAYERED_PANE;
    }
  }
}
